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<TITLE>Magic-7.3 Command Reference</TITLE>
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<H1> <IMG SRC=graphics/magic_title2.gif ALT="Magic VLSI Layout Tool Version 7.3">
     <IMG SRC=graphics/magic_OGL_sm.gif ALIGN="top" ALT="*"> </H1>

<H2>def</H2>
<HR>
Read or write DEF format files.
<HR>

<H3>Usage:</H3>
   <BLOCKQUOTE>
      <B>def</B> <I>option</I> <BR><BR>
      <BLOCKQUOTE>
         where <I>option</I> is one of the following:
	 <DL>
	   <DT> <B>read</B> [<I>filename</I>]
	   <DD> Read a DEF file <I>filename</I>[<B>.def</B>]
	   <DT> <B>write</B> [<I>cell</I>]
	   <DD> Write DEF for current or indicated cell named <I>cell</I>
	   <DT> <B>help</B>
	   <DD> Print help information (command summary)
	 </DL>
      </BLOCKQUOTE>
   </BLOCKQUOTE>

<H3>Summary:</H3>
   <BLOCKQUOTE>
      The <B>def</B> command reads and writes DEF format files.  These
      files are generally assumed to be digital standard-cell based
      layouts.  The DEF format has no real concept of hierarchy.  To
      generate a valid DEF file that may be recognized by other
      software, it is necessary to have a layout with standard cells
      using the <B>port</B> method to declare input and output ports.
      In particular, the <B>port class</B>  and <B>port use</B> are
      designed to work with the DEF read and write routines. <P>

      The technology file should have a <B>lef</B> section
      describing how LEF and DEF files should be written.  However, if
      an appropriate LEF file exists and is read prior to writing a
      DEF format file, the technology will be initialized from the
      file if it is not declared in the technology file. <P>
   </BLOCKQUOTE>

<H3>Implementation Notes:</H3>
   <BLOCKQUOTE>
      <B>def</B> is implemented as a built-in <B>magic</B> command.
      Only the critical part of the DEF definition has been
      implemented.  Some uncommon forms of syntax such as
      wire extensions are not implemented.  This is largely due
      to the incomplete nature of the LEF/DEF spec.  It is unlikely
      that such forms will be encountered in third-party input.
   </BLOCKQUOTE>

<H3>See Also:</H3>
   <BLOCKQUOTE>
      <A HREF=lef.html><B>lef</B></A> <BR>
      <A HREF=port.html><B>port</B></A> <BR>
   </BLOCKQUOTE>

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<P><I>Last updated:</I> October 7, 2004 at 1:45am <P>
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